PRISTINA, Yugoslavia (CNN) -- The general in charge of NATO's peacekeeping force in Kosovo said Tuesday that the disarmament of ethnic Albanian rebels in the Serbian province was going well and he was "broadly satisfied" with its progress.

The KLA and KFOR signed an agreement June 21 stipulating that all rebel weapons must be placed in designated storage sites by Monday at midnight. Additionally, the KLA soldiers must vacate their military positions.

KLA chief of general staff Agim Ceku said Tuesday that half of his 20,000 troops had gathered in 45 personnel assembly areas across the province.

"The greatest part of our soldiers have got a leave to go and attend to their family problems," Ceku said at a news conference outside KFOR headquarters in Pristina. "But these things are carried out in civilian clothes and with no arms."

Jackson said that, since the KLA was an "irregular army" that had just gotten out of a "bitter conflict," he was not concerned about stragglers.

"I am not in the least bit surprised that some of the soldiers have not got a clear idea at this stage of what is required of them," he said.

Ceku also denied that KLA soldiers were taking part in any reprisals perpetuated against Kosovo's Serb population as Yugoslav troops left the province. But if any are, he said, they "will be judged and punished according to disciplinary measures within" the KLA.

Meanwhile, more ethnic Albanian refugees made the journey home on Tuesday. With nearly half a million Kosovars returning to the province since the end of the war, Jackson called the rapid return "remarkable."

"At the current rate of returns, all the refugees will be back before the end of July, maybe even sooner," he said.

Most of those returnees have crossed from Albania and Macedonia on their own -- U.N.-sanctioned returns began Monday -- despite warnings that land mines, booby traps and unexploded bombs rendered much of the region unsafe.

But, Jackson said, "neither I nor anyone in UNHCR is going to stand in their way."

UNHCR, the U.N.'s refugee agency, announced Tuesday it would begin repatriating refugees from Albanian on Thursday. Ten busloads crossed from Macedonia Tuesday on their way to Pristina and Urosevac. Ten buses also traveled from Macedonia to Pristina on Monday.

While the refugees came back to what was left of their homes, war crimes investigators combed a site in Izbica where ethnic Albanians filmed the bodies of villagers they said were shot by Serb forces. But the bodies were gone -- villagers said the Serbs came back and emptied the graves.

French forensics experts at the site said they have found shell casings, however, along with hair bone fragments and bullet-riddled clothes.

Jackson, speaking in Pristina, said the evidence of war crimes uncovered so far "is probably larger than any of us really wanted to believe."

While the KLA began its disarmament process and refugees came back home, the opposition to Yugoslav President Slobodan Milosevic staged its first public rally since the end of NATO's air war against Yugoslavia.

Between 3,000 and 5,000 people turned out in Cacak, about 90 miles south of Belgrade, even though local police warned the group that the demonstration was illegal and attempted to persuade organizers to call it off. The demonstrators, angry over the outcome of the Kosovo war and an economy shattered by NATO's intense bombing campaign, demanded Milosevic's resignation.

A small explosion interrupted the rally, but there were no injuries and the demonstration continued without further incident.

Opposition to Milosevic has surfaced briefly in recent years, but with no success at a sustained effort to put pressure on the president. Leaders of the movement hope that this time will be different.

"I think the people are increasingly aware that Milosevic and his policies have been defeated," declared Goran Svilanovic, head of the opposition Civic Alliance party, on Monday. "People can feel he is finished and they are no longer afraid."